Recently published research suggests that the membrane bound immunoglobulin of B-lymphocytes differs physically and chemically from the immunoglobulin secreted by plasma cells. The objectives of this proposal are to examine the molecular basis for the unique physical and chemical characteristics of membrane bound immunoglobulin, to determine whether changes in these characteristics occur during the differentiation of B-cells, and to investigate the mechanism by which the membrane-immunoglobulin association is stabilized. A biochemical approach employing the method of charge-shift electrophoresis and the techniques of protein chemistry will be used. The work will lead to a better understanding of how interactions with the surface antigens and receptors of cells control intracellular biochemical reactions.